Field
Exemplary embodiments of the present invention relate to a light emitting device, and more particularly, to a light emitting diode chip that is resistant to electrostatic discharge, and a light emitting diode package including the same.
Discussion of the Background
Generally, GaN-based compound semiconductors are formed by epitaxial growth on a sapphire substrate, which has a similar crystal structure and lattice parameter thereto, in order to reduce lattice defects. However, epitaxial layers grown on the sapphire substrate may have many types of crystal defects, such as V-fits, threading dislocations, and the like. When high voltage static electricity is applied to a light emitting diode from outside, current is concentrated in crystal defects in the epitaxial layers, thereby causing diode breakdown.
Recently, the number of applications of high brightness/high output light emitting diodes (LEDs) has increased, not only to backlight units of LED TVs, but also to luminaries, automobiles, electric signboards, facilities, and the like. Accordingly, there is an increasing demand for the protection of light emitting devices against static electricity.
For LEDs, it is desirable to secure a semi-permanent lifespan using an ESD protection device having excellent electric reliability. It is very important to secure reliability of LEDs with respect to electrostatic discharge (ESD), electrical fast transient (EFT), which refers to sparks occurring in a switch, and electrical surges resulting from lightning and the like.
Generally, when packaging a light emitting diode, a separate Zener diode is mounted together with the light emitting diode to prevent electrostatic discharge. However, the Zener diode is expensive and several processes are used for mounting, thereby increasing manufacturing costs, as well as the number of processes for packaging the light emitting diode. Moreover, because the Zener diode is disposed near the light emitting diode in an LED package, luminous efficacy of the package is reduced as a result of absorption of light by the Zener diode, thereby deteriorating light yield of the LED package.
On the other hand, various attempts have been made to provide a light emitting diode chip resistant to ESD using a stacked structure of epitaxial layers in the light emitting diode chip. For example, a super lattice layer may be disposed between an n-type semiconductor layer and an active layer. With this structure, the super lattice layer can reduce lattice defects in the active layer, thereby providing a light emitting diode chip resistant to ESD. However, this technique still does not provide good yield.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and, therefore, it may contain information that does not constitute prior art.